Starch and hydrocolloid mixtures are often employed to modify and control the texture of food products. It has been well established that the addition of hydrocolloids increases the viscosity of starch. Konjac flour interacts synergistically with hydrocolloids such as xcexa-carrageenan, as well as other hydrocolloids in modifying the texture of food products. Yoshimura, M., et al., J. Agric. Food Chem., 44:2970 (1996).
Konjac flour is produced from the tuber of the plant Amorphopallus konjac. Konjac flour contains a high molecular weight glucomannan polysaccharide consisting of mannose and glucose in a molecular ratio of approximately 3:2 respectively, with beta-1,4-linkages. The molecular weight is greater than 300,000 daltons. Hydroxyl groups are present throughout the molecule providing some hydrophilicity, thereby imparting water solubility. Acetyl groups are important in controlling the gelling mechanism, but not critical in water solubility.
Konjac flour has several properties that can be readily used in food formulations. When konjac flour is mixed with water, the small sacs containing the flour swell as they absorb the water. The viscosity of the dispersion begins to increase as the sacs swell with water and release the konjac flour. Konjac has a high capacity for water absorption. Tye, R. J., Food Technology, 45(3):82-92 (March 1991). Therefore, the addition of konjac flour may alter the viscosity of the preparation. Konjac flour may be used with starch, with or without other gums or stabilizers present. Generally, as the concentration of konjac increases in the presence of many starches there is a concomitant increase in the viscosity of the dispersion mixture. Konjac flour functionally interacts with most starches to give a considerable increase in viscosity that is maintained during cooking and cooling. Tye (March 1991).
Another attractive feature of konjac is its thermal stability. Generally, gels formed by polysaccharides other than konjac will lose their network structure at high temperatures. Konjac is different in that it can maintain its network lattice even at relatively high temperatures while other polymers will lose their gel structure at these same temperatures. Tye (March 1991).
Dietary fiber has been suggested as an effective food ingredient in the prevention of such diseases as diabetes, hyperlipidemia, coronary heart disease, colon diverticulum and colon cancer. The reason ascribed to fiber""s efficacy is the high viscosity that it possesses. Jenkins, D. J. A., et al., British Med. J., 1:1392 (1978). Recent studies suggest that a high-fiber diet in conjunction with konjac flour as a supplement confers a beneficial effect on lipid and glucose levels that actually might retard or prevent the formation of atherosclerosis in a diabetic patient. Doi, K., Eur. J. Clin. Nutr., 49, Suppl. 3:190 (1995). Arvill and Bodin examined the effects of soluble fiber konjac on serum cholesterol in adult human males. The results of their study show that konjac is an effective cholesterol lowering dietary adjunct. Arvill, A. and L. Bodin, Am. J. Clin. Nutr., 61:585-589 (1995).
The present invention pertains to compositions and methods of making a low viscosity glucomannan (e.g., konjac) composition comprising glucomannan and a viscosity lowering compound, such as polysaccharides (e.g., maltodextrin, inulin and hydrolyzed guar gum) and proteins, present in amounts that when dispersed in an aqueous medium results in a low viscosity glucomannan dispersion, compared to a glucomannan dispersion without the viscosity lowering compound present.
The present invention also pertains to methods of making a low viscosity glucomannan composition comprising dispersing a viscosity lowering compound with glucomannan (e.g., konjac) in an aqueous medium to form a low viscosity dispersion resulting from the interaction of the two components.
In one embodiment of the invention, the glucomannan is konjac flour and the viscosity lowering compound is the polysaccharide maltodextrin. In this embodiment, maltodextrin and konjac are heated to a temperature sufficient to disperse the two components in an aqueous medium. The viscosity of the dispersion significantly drops to yield a low viscosity composition resulting from the interaction of the two components.
In another embodiment of the invention, the viscosity lowering polysaccharide can be maltodextrin, hydrolyzed guar gum, inulin or combinations thereof. One or more of these viscosity lowering compounds are dispersed in an aqueous medium with glucomannan (e.g., konjac) to form a low viscosity dispersion resulting from the interaction of the components of the dispersion. The presence of hydrolyzed guar gum and/or inulin also provides a source of dietary fiber.
The konjac compositions of the present invention can be used to stabilize or texturize food and beverage products, such as in the production of ice cream, and as a fat substitute in a variety of reduced fat, low fat and fat free foods and beverages, such as cakes, pudding type desserts, butter, peanut butter, salad dressings, sauces, margarine, cream cheese and other spreads, snack dips, mayonnaise, sour cream, yogurt, ice cream, frozen desserts, fudge and other confections, and skim milk. The konjac compositions can be incorporated into fat free, reduced fat, low fat and fat containing cheeses, such as natural, processed and imitation cheeses in a variety of forms (e.g., shredded, block, slices and grated). The konjac compositions are also useful, as for example, a shortening, in baked goods such as cakes, pies, brownies, cookies, breads, noodles, snack items, such as crackers, graham crackers and pretzels, and similar products.
The ability to modulate (i.e., increase or decrease) the viscosity of the compositions of the invention is advantageous in the preparation of food products and beverages. In another embodiment of the invention, a method for preparing a high viscosity food product and beverage from a low viscosity starting preparation is described. A combination, for example, of a high use level of konjac and low dextrose equivalent value (hereinafter xe2x80x9cDExe2x80x9d) maltodextrin can be used in systems that require a low process viscosity, such as spray drying or filling operation. Subsequent hydrolysis of the maltodextrin, such as by using xcex1-amylase or acid hydrolysis, in the mixture will result in the increase of viscosity in the product.
Since konjac has been shown to beneficially affect lipid and glucose levels, the compositions of this invention can be used as therapeutic agents therefor. Accordingly, the invention pertains to a method for lowering blood glucose in a mammal, including human, in need thereof by administering an effective therapeutic dose of the compositions described herein to a mammal in order to reduce the blood glucose level.
In another aspect of the invention, the compositions of this invention can be administered to a mammal, including human, for the purpose of lowering blood cholesterol levels.